The link you posted is for the T8 5.0 Bulb. The HO T5 Bulb is a lot better than the T8 bulb. HO T5 fixtures are more efficient and produce a brighter and better looking light. Most people use T8 as they already owned the fixture when HO T5 fixtures were considerably more expensive, but since they have came down in price more and more people are upgrading to the T5.
I personally don't like Zoo Med lighting products and would recommend other brands over them.